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-rw-r--r--blockdev.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/blockdev.c b/blockdev.c
index 9068c5b1d0..af4e239b93 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -257,6 +257,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
     DriveInfo *dinfo;
     BlockIOLimit io_limits;
     int snapshot = 0;
+    bool copy_on_read;
     int ret;
 
     translation = BIOS_ATA_TRANSLATION_AUTO;
@@ -273,6 +274,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
 
     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
     ro = qemu_opt_get_bool(opts, "readonly", 0);
+    copy_on_read = qemu_opt_get_bool(opts, "copy-on-read", false);
 
     file = qemu_opt_get(opts, "file");
     serial = qemu_opt_get(opts, "serial");
@@ -546,6 +548,10 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
         bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
     }
 
+    if (copy_on_read) {
+        bdrv_flags |= BDRV_O_COPY_ON_READ;
+    }
+
     if (media == MEDIA_CDROM) {
         /* CDROM is fine for any interface, don't check.  */
         ro = 1;